Conduit and method of production



Feb. 17, 1931. T. E MURRAY 1,793,241

CONDUIT AND METHOD 0F PRODUCTION K Filed Nov. 7, 1924- 7770/7706 f Mar/"a PatentedV Feb. 17, 1931 THOMAS, E. MURRAY, or, BROOKLYN; NEW YORK; .ios'nrri BRADII'RY- MURRAY, i

A MURRAY, .RXRcUTORs or: SAID THOMAS E., -MURRAYDRo11AsED, AssIGNoRs To 'METROPOLITAN DFNIUORv CORPORATION, A OOR- THOMAS E. MURRAY, JR., AND JOHN F.

PORATION OF NEW YORK OONDUIT AND METHOD or PRODUOTION ,f

ities. The` accompanying drawings-'illus 'f trate Vembodiments of my invention. Y

' F`g.`1 is a cross-section of'a -oor illu-strat- `ingyin place a coreV for 'forming the; conduit lthe-rein;A Y I "'Fig.2'isja similarvievv'vvith thecoreremoved; Y

' Figs. 3 and 4 larevertioal and horizontal 'sections of the same respectively, in longitudinal direction; -5 I: Figs. 5, 6, 7 and 8 are[.cross-sections illustratinglthe'applic'ation of thel invention to other? styles of conduit.

Thein'vention` is illustrated in connection ,with the concrete'ioor of a building, but it may be used in connection v withA` various street conduits, and's'o forth; ,y Y

Referring to Fig. l, a floor is shown composedof a base l generally of comparatively :other structures; such, for example, as Walls,

fcoarse concrete and a top layer 2 of comparatively ine concrete.` A! conduit is to be formed therein near the uppersurface With' outlets for taking out electric Wires or other utilities. The coarse concrete `is'irst laid iWith recesses 3 in the upper part and inthese recesses ,are located removable cores 4.

Q'Ihese cores are {prefer-ably of` highlyresilien'trubber with a comparatively thick wall :ad'aptedto withstand the pressure involved? inl laying 4and tamping the concrete around. Afterfthe concrete has hardened the core is Withdrawn `bypulling it outk endwise. l Its l composition is suchv that Va longitudinal pull fwvillco'ntract it transversely sufficiently 'to free it from the surrounding concrete and topermit'its withdrawal, and it is of such Vresiliency that it will automatically resume its original shape for reuse.' Cores ofthis characterare-more' fully described in pre' vious pending applications: of mine. O11 top of the'core is laid a cover plate 5 of metal or other comparatively sti material intendedto remain in place. Theplatehas side portions l6 serving to embrace the circular core-so as to holdit'ina straight line againsty its natural tendency to `bend andv twist.

" cables through the conduit; l

7, 1924. serial No. 748345.?Y

plate will be correspondingly curved Tand willfhold the core in proper line.l The `plate' is providedalso with lateral .flanges/Tex# tendingv outward lfrom the core. lAfter the core Yandplate are in4 position the space aroundl them isrflled with the ifne concrete 2, the" latter being laid a't the ldesired top level: When? the concrete ishardened the rubber core isWithdraWn, leaving al conduit substantially vcircular in cross-section with .the cover plate yoverthe top of it imbedded at its edges in the concrete and thus'firmly held in place during Withdrawal' of the core as Well as duringthef subsequent' drawing vof The cover plateisformed` at intervals With -outletsS `(Fig. 3) leadingto the *topy ofthe ioor I, through lWhich connecting Wiresor ppesmay be passed for utilization in appabottom plate-having'similaroutlets leading ,y

.to thelower surface. f ,Y f l The plates -or .linersthus vprwided at the side of the conduit on'which'theoutlets are to be vmade serveto holdthel duct in shape .and to prevent injury to the concrete around the outlet. And' in the stretches' `,between outlets `they protectV the conduit from accidental injuryy as'by the'` dropping of,v a .heavy Weight on the' top thereof. They. may i be providedthroughout` the lengthof the Y conduit oron'lyadjacent ytothe intended .outlets, as desired.- fr .l

I have illustrated also in vconnection `.with Figs. 1 to 45a method.; of laying conductors in the'conduit during the formation ofthe latter; and this vmethod may be applied-also to the conduits shovvnin the other figures and indeed to conduits of various-other styles., For this purpose? the corev is formed VVwith recesses 9 extending'longitudinally and ljustlarge enoughto accommodate the con du'ctor'slO which :are laid in 'therecessesibe- -fore theconcrete isapplied. Theconductors surrounding concrete to anchor the conductors in place.- For greater securityagainst water which may get into the coi'icrete these loops 11 may be surrounded with a coating of plastic insulating material 12 before the concrete is laid.

Whenthecore is withdrawn, thereis left 'a conduit 12, Figs. 2, 3 and 4, the wall of which is formed partly by a cover plate and partly bythe concrete itself, finishedwith a very smooth surface produced the use of a rubber core, and with conductors anf chored at intervals to the concrete sol as to be held in place, and vexposed -betweensuch anchoring points so 'asto permit connections at any desired one of the outlets 8 which are provided. Additional c'ondiictors.` may be threaded into the `duct .resting on the bottom and out of contactwith the conductorsl0. 0r such additional conductors may be laid in the conduit, similarly to the conductors 10 and at other points on the periphery of the core by suitably grooving the latter.

Fig. 5 illustrates the application ofthe invention to the making of a ksquare conduit. The rubber core v13 in this case* is 'square and the cover plate 14 has its side portions 15 -vertical instead of flared as in Fig. 1. According `to Fig. 6 a rectangular conduit 'of suitable width, so as toeccoinniodate a greater number Vof conductors 'or other Yutili'- ties, is' formed with the 'aid of a wide rectangular coi-e 16 Vand a correspondingly wide cover plate 117 with Vvertical side portions `1,8 embracing the upper 'part of the core. j

Fig. 7 illustrates the forming of two separate -paiaillel conduits, useful where two condnotors or sets of condnotors inust be kept lentirely separate. n 4This` figure illustrates also the of cores 19 which are .nearly-solid, having only a ine central hole. This illustrates also afdiifeien't style ofc'o'ver Yplate 20. l This lies' no eide portions embracing the core and is anchored in Ithe con'ci'e'teinerely by,

einen ii'anges 21 on its edges. 'The twoconduits have to 'belaid fairly 'close together Vwith a well tamped wall 22 ofco'ncrete between them, sotha't it is advisable to use etilder eores than iii tlie other cases illus,-

treted. Also they are eogeioeetogether as to plates and lateral lia-vnges ask in 'the other The 'fiaiigesfiQl entend tlpwar'd into the thi-n lrayervoi 'iiiie 'concrete 'at the top and Vserve to reinforce it against ci-aolzin-ggthe flanges on the plates''in the oth'e'rfigure's serve also to afdue't throughout its length, the plate will yhaving' a fla-t center and having anges im@ n act to electrically ground the `entire system.

The outlets 8 will generally be arranged at predetermined points. When a connection is to be made at. some other pointthe duct can be located by the aidof the outletV 8. That is, the duct will be located on the line between two outlets.` Ve may then drill Vfro'rnthetop of the floor'down into the duct, tapping themetal plate on the top and screw- Aing a fitting into it, or fastening thelfi'tting in any other usual or'suitable way.

Openings may be drilled into the duct even when the latter is formed without a top plate7 andthe fitting cemented or otherwise attached to the concrete. The making of the duct flat on the top facilitates the drilling operation and is particularly advantageous where there is no metal plate forming a wall on the conduit. See Fig. 8 for example. Here a conduit 23 is formed witha flat; top 24. .The concrete above is drilled, a sleeve 2 5. is cementedtherein 'and a tubular fitting 26 is screwed into the sleeve, thus makingeasy therintroduction andconnectionof the wires. This flat top can be drilled or tapped better'than the round top which has been previously proposed,. especially in the .smaller sizes of conduit.

Though I havedescribed ticularity of detail certain embodiments of my inventiony yet it is not tojbe understood therefrom that the invention :is restricted to the: particularembodiments disclosed. jVariouslmodications may be' made by those `skilled in the 'Ia-rt without departure .from the invention as deiined in the followingv claims. What I claim is 1 Astructure of concretel ortho like having a conduit therein, the wall of which --is formed pa'rtly by the surrounding concrete and partly by, a separate plate having Hanges imbedded in the concrete. j t f 1 ll 2. A structure ofA concrete or the likefo'om- -prising a base portion of coarse concrete with recesses in=its facefa'nd ai layer of line concrete applied 'on said face --and having a 4condui-t located in the tine concrete, the wall o f 'theconduit extending below the general level .of the fine concrete and into said recesses and being formed partly by the surrounding l? concrete and partly by a separate plate.

f 3. A structure of lconcrete or theV like comprisi'nga base portion ofcoar'se concrete, and a surface layer of fine `concrete and having fa conduit located inthe fine concrete. the wall of the conduit being 'formed -part-ly by the with great 'p'ar- IOO ' los in)k Vino

surrounding concrete -and partly by a separate plate having flanges imbedded in the concrete.

4. A structure of concrete or the like .having a conduit therein the lower portion of which is formed by the concrete and the upper portion of which is :formed by falplate bedded in the concrete. Y

5. A structure of concrete or vthelikel hav ing a conduit thereinv the lower portion and vpart of the sides of which are formed by the concrete and theupper portion and remainv der of the sides Yof which are formed by a plate. Y Y A 6. A struoture'of concrete or the like oomprising a base portion of ooarseconorete With recesses in its face, and a layerof fine oon'- orete applied on said face, and having a oonduit formed and enclosed in said line concrete, a cover plate embedded in andveovered by said concrete and extending over the top surface of said conduit, the wall of the oonduit extending below the general level of the fine concrete and into said reeesses.

In Witness whereof, I have hereunto signed myname.

Y THOMAS E. MURRAY.

Aso YY 

